Here's the one-year perspective (moved from Boston last June), from someone who lives Downtown and doesn't own a car (has a bicycle):

Pros:

• Weather: usually sunny and warm, occasionally cloudy and cool (though it does get a bit monotonous...)
• Produce: all year round you get amazing fruit and veggies

Ehs:

• Public transit: Trains are OK (wish they went farther out to the coast), buses are fairly unreliable (especially if one never comes); and the time-per-distance isn't great
• Food: You really have to hunt for the good spots, and for the most part they're always more expensive than $25/meal (in Boston, you could easily do $15 and great, diverse food was everywhere)
• Meeting people (friends): Meet-up groups are everywhere, and there's usually something awesome/interesting to do every weekend if you can find it, but traveling around is difficult
• Neighborhoods: there's a pretty good diverse set of neighborhoods, but not as distinct as I felt NYC was
• Rent: I was paying about the same in Boston (though I'm Downtown and splitting with my partner, to give perspective)
• Geek culture: Boston is a really intellectual city; you really have to search around in LA for both people and events

Cons:

• Networking (professional): Feels like it's more difficult than other cities (eg., Boston, NYC, San Fran) & especially harder to get around and meet people at events, since the city is so large
• Transportation: traffic (if you drive a car); distance (if you ride a bike/rely on public transit)
• Good bagels and pizza are RARE

Takeaways:

• Keep in mind that LA is really a dozen cities all next to each other. It's really big and that hinders some of the benefits.
• Take the opportunity to meet a few people before arriving here, because it'll help meet others easily. Otherwise, rely on r/LA's Meetup group (something which I personally hope to take advantage of more this summer)